I can't get the microwave to heat. I've disassembled the unit and tried testing the components with a multimeter. The magnatron registers a .03 ohm reading at the terminals and nothing from the terminal to the casing. I've wired the diode in series with a 9v battery and was able to get 3V one direction but none another, so I believe that one checks out. I've done simliar tests with the door switches and they are all operating correctly, including the high voltage capacitor. I'm kind of at my wits end! Any advice????